package com.zyk.leetcode;

/**
 * @author zhangsan
 * @date 2021/4/3 21:56
 */
public class J12 {
    public static boolean exist(char[][] board, String word) {
        char[] words = word.toCharArray();
        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[0].length; j++) {
                if (dfs(board, words, i, j, 0)) return true;
            }
        }
        return false;
    }

    static boolean dfs(char[][] board, char[] word, int i, int j, int k) {
        if (i >= board.length || i < 0 || j >= board[0].length || j < 0 || board[i][j] != word[k]) return false;
        if (k == word.length - 1) return true;
        board[i][j] = '\0';
        boolean res = dfs(board, word, i + 1, j, k + 1) || dfs(board, word, i - 1, j, k + 1) ||
                dfs(board, word, i, j + 1, k + 1) || dfs(board, word, i, j - 1, k + 1);
        board[i][j] = word[k];
        return res;
    }

    // for test
    public static void main(String[] args) {
        // board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCCED"
        char[][] board = {
                {'A', 'B', 'C', 'E' },
                {'S', 'F', 'C', 'S' },
                {'A', 'D', 'E', 'E' },
        };
        String word = "ABCCED";
        System.out.println(exist(board, word));
//        System.out.println(dp(board, word));
    }

}
